Power and wavelength for laser engraving?

I have noticed that since I had built my 1 watt, I can cut things relatively easy. So I was wondering why don't I make a laser engraver/cutter?

I have made a 3d printer in the past and have decided to tear it apart and use the electronics to make the engraver. I'll just buy a kit then for a new printer.

I think I got everything sorted out. But the question is what combination of the wavelength and power will be the most efficient. If I'm not mistaking, 445nm is obsorbed by most colors. So that should work just fine. But I'm pretty sure that I can make a high powered IR laser. I hoping to hit 5 Watts and since it's going to be used strictly for engraving, visible color doesn't matter and it should be safe. I have eagle pair safety glasses because I know that what you can't see can hurt you...

So my main question is, would I be better off with a 5 watt 445nm laser or 5 watt IR laser

I'm looking for fast burning so I can move the head as fast as possible.

Thanks!